Disk drives are widely used in computers, consumer electronics and data processing systems for storing information in digital form. The disk drive typically includes one or more storage disks and one or more head suspension assemblies. Each head suspension assembly includes a slider having an air bearing surface, and a read/write head that transfers information to and from the storage disk. The rotation of the storage disk causes the slider to ride on an air bearing so that the read/write head is at a distance from the storage disk that is referred to as a “head-to-disk spacing” (also sometimes referred to herein as a “flying height”).
Because today's disk drives utilize storage disks having increasingly high densities of data tracks, adjusting the head-to-disk spacing to maintain a relatively low flying height during varying operations of the disk drive has become of great importance. For instance, nominal fly heights can now be as small as 5 nanometers or less. However, this desire for a small head-to-disk spacing must be balanced with tribological concerns in order to avoid damage to the read/write head and/or the storage disk, as well as loss of data.
Recently, systems and methods for controlling the head-to-disk spacing have been advanced in the disk drive industry. For example, the slider can include a read/write head and a separate slider mover to which the controller directs electrical current. A temperature change of the slider mover occurs as a result of the electrical current, resulting in a deformation of a portion of the slider, thereby influencing the head-to-disk spacing. In the past, accurately monitoring and/or determining the actual head-to-disk spacing during in situ operation has been elusive. Further, attributing a specific change in the head-to-disk spacing to one or more causes in a conventional disk drive has been particularly challenging.